Editor's note: This article is taken from Elias Alexander's dailytidings.com blog Ecovillager.

In recent years, since the environmental crisis has come to be known to more people, there has been a lot of talk about "sustainability." You see it in everything from development to housing, food production to products in the supermarket. But rarely is sustainability defined. It tends to imply that whatever thing it is attached to is somehow green or environmentally friendly. I therefore offer my definition, in hopes that this will clear things up.

An activity or institution is sustainable if it can be continued into the indefinite future. Than means that it would only draw resources as quickly as they could be replaced by the natural cycles of the planet, and only emit wastes as quickly as those wastes can be assimilated and processed by the planet.

In many of my articles I talk about becoming "more sustainable." What does this mean? It means that whatever activity I'm describing could be carried out for a longer time before it is forced to cease.

A sustainable use of fossil fuels would be at a rate low enough that they would be replenished by the time they would be used up. Since it takes millions of years for coal and oil to form, this would be quite slow.

Defining a sustainable social organization is a bit more difficult, since humans and societies continually change. I would say that a sustainable social organization would be one that changes little enough to (1) not cause calamitous population loss (war, famine, disease), and (2) pass down the knowledge of how to live in a way that uses resources at a sustainable rate.

Note that some sustainable social organizations have included war, such as some Native American systems, which lasted for thousands of years but were hardly peaceful. War in indigenous societies all over the world, however, is almost always very low in casualties, and is less a disruption of life than a part of it (which is not to say it does not cause pain and sufferning).

Jared Diamond's book "Collapse" might provide more insight into societies that have and have not been sustainable.

Elias Alexander is an Ashland resident studying in Findhorn, Scotland, one of dozens of intentional communities dedicated to sustainable living that dot the European map. After undergoing a month-long intensive Ecovillage training course there, he will spend the next three months visiting some of those communities. He intends to find out what they are doing to be sustainable, how they are doing it and what aspects can be expanded to a larger segment of the population. In articles here, you can join him on this journey.